Document strftime %Ob and %OB as C2X features

C2X standardizes strftime %Ob and %OB support.  This patch updates the
glibc manual to say these are C2X features.

Note: C2X seems unclear to me about whether %h being equivalent to %b
means %Oh is thereby allowed and equivalent to %Ob; I've asked WG14.

Tested with "make info" and "make pdf".

2019-08-15  Joseph Myers  <joseph@codesourcery.com>

	* manual/time.texi (strftime): Document %Ob and %OB as C2X
	features.

* Joseph Myers:

> C2X standardizes strftime %Ob and %OB support.  This patch updates the
> glibc manual to say these are C2X features.
>
> Note: C2X seems unclear to me about whether %h being equivalent to %b
> means %Oh is thereby allowed and equivalent to %Ob; I've asked WG14.
>
> Tested with "make info" and "make pdf".
>
> 2019-08-15  Joseph Myers  <joseph@codesourcery.com>
>
> 	* manual/time.texi (strftime): Document %Ob and %OB as C2X
> 	features.
>
> diff --git a/manual/time.texi b/manual/time.texi
> index bfa46dd45b..aeb24382ea 100644
> --- a/manual/time.texi
> +++ b/manual/time.texi
> @@ -1352,7 +1352,7 @@ alternative numeric symbols.
>  With @code{%B}, @code{%b}, and @code{%h}: use the grammatical form for
>  month names that is appropriate when the month is named by itself,
>  rather than the form that is appropriate when the month is used as
> -part of a complete date.  This is a GNU extension.
> +part of a complete date.  This is a C2X feature.
>  @end table
>  
>  If the format supports the modifier but no alternative representation
> @@ -1372,13 +1372,13 @@ The full weekday name according to the current locale.
>  @item %b
>  The abbreviated month name according to the current locale, in the
>  grammatical form used when the month is part of a complete date.
> -As a GNU extension, the @code{O} modifier can be used (@code{%Ob})
> +As a C2X feature, the @code{O} modifier can be used (@code{%Ob})
>  to get the grammatical form used when the month is named by itself.
>  
>  @item %B
>  The full month name according to the current locale, in the
>  grammatical form used when the month is part of a complete date.
> -As a GNU extension, the @code{O} modifier can be used (@code{%OB})
> +As a C2X feature, the @code{O} modifier can be used (@code{%OB})
>  to get the grammatical form used when the month is named by itself.
>  
>  Note that not all languages need two different forms of the month

C2X (in the form of N2385) is ambiguous on the relative meaning of %B
and %OB, so the precise meaning defined in the manual is still a GNU
extension.  Not sure if that matters.  I do not have objection to this
patch.

Thanks,
Florian

On Thu, 15 Aug 2019, Florian Weimer wrote:

> C2X (in the form of N2385) is ambiguous on the relative meaning of %B
> and %OB, so the precise meaning defined in the manual is still a GNU
> extension.  Not sure if that matters.  I do not have objection to this
> patch.

Here is a version of the patch that tries to clarify that issue.


Document strftime %Ob and %OB as C2X features.

C2X standardizes strftime %Ob and %OB support.  This patch updates the
glibc manual to say these are C2X features, while noting that the
details of what is the alternative form of a month name are not
specified in C2X.

Note: C2X seems unclear to me about whether %h being equivalent to %b
means %Oh is thereby allowed and equivalent to %Ob; I've asked WG14.

Tested with "make info" and "make pdf".

2019-08-21  Joseph Myers  <joseph@codesourcery.com>

	* manual/time.texi (strftime): Document %Ob and %OB as C2X
	features.

diff --git a/manual/time.texi b/manual/time.texi
index bfa46dd45b..c5f5b94b67 100644
--- a/manual/time.texi
+++ b/manual/time.texi
@@ -1352,7 +1352,11 @@ alternative numeric symbols.
 With @code{%B}, @code{%b}, and @code{%h}: use the grammatical form for
 month names that is appropriate when the month is named by itself,
 rather than the form that is appropriate when the month is used as
-part of a complete date.  This is a GNU extension.
+part of a complete date.  The @code{%OB} and @code{%Ob} formats are a
+C2X feature, specified in C2X to use the locale's `alternative' month
+name; @theglibc{} extends this specification to say that the form used
+in a complete date is the default and the form naming the month by
+itself is the alternative.
 @end table
 
 If the format supports the modifier but no alternative representation
@@ -1372,14 +1376,16 @@ The full weekday name according to the current locale.
 @item %b
 The abbreviated month name according to the current locale, in the
 grammatical form used when the month is part of a complete date.
-As a GNU extension, the @code{O} modifier can be used (@code{%Ob})
-to get the grammatical form used when the month is named by itself.
+As a C2X feature (with a more detailed specification in @theglibc{}),
+the @code{O} modifier can be used (@code{%Ob}) to get the grammatical
+form used when the month is named by itself.
 
 @item %B
 The full month name according to the current locale, in the
 grammatical form used when the month is part of a complete date.
-As a GNU extension, the @code{O} modifier can be used (@code{%OB})
-to get the grammatical form used when the month is named by itself.
+As a C2X feature (with a more detailed specification in @theglibc{}),
+the @code{O} modifier can be used (@code{%OB}) to get the grammatical
+form used when the month is named by itself.
 
 Note that not all languages need two different forms of the month
 names, so the text produced by @code{%B} and @code{%OB}, and by

21.08.2019 21:39 Joseph Myers <joseph@codesourcery.com> wrote:
> 
> On Thu, 15 Aug 2019, Florian Weimer wrote:
> 
> > C2X (in the form of N2385) is ambiguous on the relative meaning of %B
> > and %OB, so the precise meaning defined in the manual is still a GNU
> > extension.  Not sure if that matters.  I do not have objection to this
> > patch.
> 
> Here is a version of the patch that tries to clarify that issue.
> [...]

Thank you, Joseph.  This looks good.  While talking about this, I received
few complains that this piece of documentation which I wrote 1.5 years
ago is sometimes ambiguous.  It is clear that "%B" is for a full date
and "%OB" is for a standalone name of a month.  People had questions:

* what if there is only a day and a month name (not a complete date so
  people thought it should be "%OB" but the answer is "%B" because there is
  a day and a month);
* what if there is only a month name and a year (it's not just a month
  standalone so people thought it should be "%B" but the answer is "%OB"
  because there is no day);
* what if some languages (which I'm not aware of) have different rules?

Is this the right moment to improve the documentation about this?

Regards,

Rafal

On Thu, 22 Aug 2019, Rafal Luzynski wrote:

> Thank you, Joseph.  This looks good.  While talking about this, I received
> few complains that this piece of documentation which I wrote 1.5 years
> ago is sometimes ambiguous.  It is clear that "%B" is for a full date
> and "%OB" is for a standalone name of a month.  People had questions:
> 
> * what if there is only a day and a month name (not a complete date so
>   people thought it should be "%OB" but the answer is "%B" because there is
>   a day and a month);
> * what if there is only a month name and a year (it's not just a month
>   standalone so people thought it should be "%B" but the answer is "%OB"
>   because there is no day);
> * what if some languages (which I'm not aware of) have different rules?
> 
> Is this the right moment to improve the documentation about this?

I think improvements to this documentation are welcome at any time.